I'll probably modify the article to include a list of suggested prerequisites and change the heat equation to "diffusion equation", as that is less physically biased.

My real goal is for somebody with a background in mathematics (but no programming) to learn how to program FD, rather than just learn the theory. This is not really made clear by the current article and I will be adding an overview.

Thanks for the feedback though - I'd welcome any more, obviously I want the article(s) to be accessible to as many people as possible!